I would recommend updating the iThemes Sync plugin to version 2.1.12 on those sites.
https://wordpress.org/plugins/ithemes-sync/#developers
I just updated a site to wp 6.1 and I got a similar error / the site has a red dot in my sync dashboard. I tried unsync-ing and re-syncing and it gave me the error ‘An error was thrown when making a callback request to your site. Please contact iThemes support’ (I am also using the latest version of sync / v2.1.12)
-
This reply was modified 1 year, 9 months ago by
wp510.
-
This reply was modified 1 year, 9 months ago by
wp510.
Thanks @lukefiretoss
All good now.
Shame iThemes sync didn’t update their plugin sooner.